My experience, playing a character with a wounding weapon is that it's very effective, but not an obviously better choice than, say a holy weapon. [Most +2 enhancements are overpriced--Axiomatic and Anarchic only see occasional advantages in a lot of campaigns, and the burst enhancements are primarily good for people who are either insanely lucky or extremely crit focussed]
A holy weapon does its 2d6 damage which is maybe a little less than I typically get out of wounding (but it's hard to be sure). However, it also bypasses DR x/good which my wounding weapon doesn't. And it works on undead which my wounding weapon doesn't. (In fact, my character picked up a ghost touch, undead bane sword to use against undead since they're a lot of the high level encounters he faces and his main weapon might as well be +1 against them).
Another thing to consider is that sometimes straight up damage is better than con damage. Heal, heals all ability damage as well as up to 150 hp of damage. If you're counting on con damage to take down something big and then it gets a Heal spell, you're out of luck. On the other hand, if you do, say 180 points of damage instead of 145 and 5 points of con, the baddie still has 30 hit points of damage left after the Heal spell. (It doesn't come up often, but it's come up once for my character so far).
Overall, I'd rate Holy as a better enhancement for a one-weapon kind of character who has one really good weapon that he wields against all comers. It's also better for use on a ghost touch weapon since nine times out of ten, incorporeal things are undead. (And the tenth one is a freakin Eladrin from the Book of Exalted Deeds that'll cast Heal when you've finally beat it enough for it to notice).
For characters who use two weapons or switch between weapons, I think it's better to have Wounding on a weapon. You can have one weapon enhanced to be optimal against crittable foes and another optimized for undead/non-critable foes. If you're a two weapon fighter, you might want wounding on both weapons for the sheer viciousness of it, but you probably still want to enhance them somewhat differently so that you're prepared for all eventualities.